Cliff's attorney Eric Mabuza has confirmed he plans to sue M-Net for R25 million for what he says is unfair dismissal.

The long-time Idols judge also plans to sue the network for defamation after he was apparently called a racist.

Mabuza says they've written to M-Net and will meet with the channel's representatives this afternoon.

"We've written a letter to M-Net demanding that he be reinstated, and if they don't do that he intends to stop the auditions which are starting on 29 January. He also wants to clear his name and is looking to claim for damages."

Yamkela Ntola, a second-year candidate attorney at Cullinan and Associates, opened the case against Nicole de Klerk after she called Ntola and other professionals at the Queen's Plate horse racing event, the k-word repeatedly.

She later apologised on Twitter, saying she's embarrassed by what she'd said.

This is the latest in a string of racist comments made over the past few weeks.